Global Positioning System Applications Research Articles

Applications of New Fuzzy Inference-Based Tracking Loops for Kinematic GPS Receiver

Carrier phase measurement is essential for high-accuracy measurement in kinematic global positioning system (GPS) applications. For GPS receiver design, a narrow noise bandwidth is desired to decrease phase jitter due to thermal noise. However, this bandwidth will deteriorate the capability of the tracking loop and result in cycle slipping. Based on bandwidth adjustment criteria, a novel intelligent GPS receiver is proposed for solving the carrier phase tracking problem in the presence of high dynamic environments. A phase error estimator is developed in the carrier loop to conduct the phase error signals; i.e., frequency and frequency ramp errors. Two kinds of fuzzy inference (FI)-based approaches, fuzzy logic control and adaptive neuro-fuzzy control methods, that are simple and have easy realization properties are designed to perform rapid and accurate control of the digital frequency phase-locked loop (FPLL). A new design procedure for kinematic GPS receiver development is also presented. The computer results show that the FI-based receivers achieve faster settling time and wider pull-in range than the conventional tracking loops while also preventing the occurrence of cycle slips.

Development of an intelligent logistics fleet management system: an integrated approach

For Small-and Medium-Sized Enterprise (SME) logistics service providers, delivery and transportation management is usually based on simple communication systems such as the use of fax, mobile phone, etc. This causes time delays to occur more frequently for SMEs than would be the case with an asset-based organisation. Moreover, the absence of well developed logistics management systems exacerbates the situation. In fact, the continuous increase in efficiency of delivery in Hong Kong and Pearl River Delta Region has driven many logistics service companies to integrate mobile technologies with their fleet management system for tracking orders in a real time situation. This paper describes an Intelligent Logistics Fleet Management System (ILFMS) for third party logistics providers using the integration of mobile technologies, the application of Global Positioning System (GPS) and a Rule-Based Expert System (RBES) for route optimisation. By applying ILFMS in Extrans International (HK) Limited, it is found that dispatching efficiency is greatly enhanced.

Performance evaluation of shorted annular patch antennas for high-precision GPS systems

Even with the advances in signal processing, multipath error remains the major error source of high-precision global positioning system (GPS) applications. One of the most valid means to improve the accuracy of these systems is an appropriate design of the receiving antenna. Unfortunately, in many cases, the low-multipath-radiation requirements are very difficult to satisfy especially when physical constraints have also to be considered. As a possible solution, a study on the multipath rejection performances of shorted annular patch (SAP) antennas is presented here. In the first part, the SAP radiation characteristics will be deeply analysed by designing and testing three different antennas. Then, the results of a comparative test conducted on a GPS facility will be used to assess the on-field performances of the three prototypes. This experimental validation will show that a significant improvement of the SAP performances can be achieved when the reduced surface wave criterion, which has been widely adopted as a design rule in previous works, is relaxed and a trade-off between all the low-multipath-radiation requirements is considered. Moreover, comparison with two commercial GPS antennas will reveal that SAPs can be a very attractive and useful solution in high-precision GPS systems where severe physical constraints are imposed.

A Compact Variable Rate Sprayer for Teaching Precision Agriculture

A compact variable rate sprayer for use in teaching precision agriculture was developed and field tested. A 3.57-m (11.7-ft) boom-type field sprayer with a 227-L (60-gal) tank was used as the base unit. Off-the-shelf Global Positioning System and variable rate application components were modified as necessary and installed on the base unit. The cost of the completed variable rate sprayer was approximately $9700. For field testing, a 12.8-m (42-ft) wide 91.4-m (300-ft) long test course was laid out and spraying prescriptions were written for field speeds of 2.74 and 5.47 km/h (1.7 and 3.4 mph). With a 2-s delay programmed into the unit, the mean position error was 0.37 m (1.23 ft) at 2.74 km/h (1.7 mph) and 0.77 m (2.51 ft) at 5.47 km/h (3.4 mph). Once the sprayer traveled into a prescribed spray zone, a mean distance of from 0.87 m (2.85 ft) (for low speed, low application rate) to 3.53 m (11.58 ft) (for high speed, high application rate) was traveled before the sprayer output initially reached the prescribed rate. The sprayer output stabilized at the prescribed rate at a mean distance of 9.59 m (31.45 ft) (high speed, high application rate) to 13.61 m (44.64 ft) (low speed, low application rate). The variable rate sprayer will be used in undergraduate and graduate classes and in workshops for agriculture teachers, Extension agents, and producers.

ABRP: Anchor-based Routing Protocol for Mobile Ad Hoc Networks

Ad hoc networks, which do not rely on any infrastructure such as access points or base stations, can be deployed rapidly and inexpensively even in situations with geographical or time constraints. Ad hoc networks are attractive in both military and disaster situations and also in commercial uses like sensor networks or conferencing. In ad hoc networks, each node acts both as a router and as a host. The topology of an ad hoc network may change dynamically, which makes it difficult to design an efficient routing protocol. As more and more wireless devices connect to the network, it is important to design a scalable routing protocol for ad hoc networks. In this paper, we present Anchor-based Routing Protocol (ABRP), a scalable routing protocol for ad hoc networks. It is a hybrid routing protocol, which combines the table-based routing strategy with the geographic routing strategy. However, GPS (Global Positioning System) (Kaplan, Understanding GPS principles and Applications, Boston: Artech House publishers, 1996) support is not needed. ABRP consists of a location-based clustering protocol, an intra-cell routing protocol and an inter-cell routing protocol. The location-based clustering protocol divides the network region into different cells. The intra-cell routing protocol routes packets within one cell. The inter-cell routing protocol is used to route packets between nodes in different cells. The combination of intra-cell and inter-cell routing protocol makes ABRP highly scalable, since each node needs to only maintain routes within a cell. The inter-cell routing protocol establishes multiple routes between different cells, which makes ABRP reliable and efficient. We evaluate the performance of ABRP using ns2 simulator. We simulated different size of networks from 200 nodes to 1600 nodes. Simulation results show that ABRP is efficient and scales well to large networks. ABRP combines the advantages of multi-path routing strategy and geographic routing strategy--efficiency and scalability, and avoids the burden--GPS support.

The use of GPS for the estimation of precipitable water vapour for weather forecasting and monitoring in South Africa

The propagation of the Global Positioning System (GPS) signal from the satellite to the receiver is affected by, among other factors, the atmosphere through which it passes and, whereas the effects of the ionosphere can be eliminated by the differencing of the two transmitted frequencies, the effects of the troposphere remain one of the major sources of noise in traditional geodetic and positioning applications of GPS. This noise can, however, be turned into a signal for the meteorologist and, by applying suitable constraints and processing strategies, it is possible to estimate the amount of precipitable water vapour (PWV) in the atmosphere. The application of the GPS data for the estimation of PWV in the atmosphere is not a new concept and has been described in many publications and reports since the early 1990s. This project is, however, an attempt to test the technique using the South African network of permanent GPS base stations.This paper describes the fundamental principles and the testing of the estimation of PWV using GPS and meteorological data from a network of nine permanent GPS base stations in South Africa. The results of the GPS derived estimates have been verified against upper air measurements from radiosonde ascents from a sub-net of five of the nine stations as well as with PWV estimated from a numerical weather model (NWM).

Application of global positioning system and geographic information system in surveillance of schistosomiasis

To use the snail survey data of Yugan, Jiangxi Province as an example to evaluate the effects and advantages of global positioning system integrated with digital maps and remote sensing data in order to manage and analyze the whole country's surveillance data of schistosomiasis by using geographic information system. The data of geographic information and snail information of 20 marshlands in Yugan, Jiangxi Province were collected, and by the correction of remote sensing images based on the digital maps and index extraction, the snail current situation and trend were analyzed and expressed. A series of specific procedure images of these 20 marshlands was established and the effects of Yugan surveillance platform based on geographic information system were validated. The whole country's surveillance data of schistosomiasis might be successfully integrated with geographic information system by global positioning system and be managed and expressed, which supplies a successful platform in using the surveillance data effectively.

English

The Wyoming Department of Environmental Quality, Land Quality Division (LQD), Powder River Coal Company (PRCC) and the Office of Surface Mining (OSM), Denver embarked on a project to develop a bond release tracking system using both Geographical Information System (GIS) and Global Positioning System (GPS) technologies. This pilot project tested the use of electronic permit data, GIS software and GPS mobile computing hardware and software for tracking the reclamation and bond release status of lands within the North Antelope Rochelle Mine permit area. The GIS application involved creating an ESRI ArcGIS personal geodatabase that contains 15 feature classes with associated attribute fields. The Personal Geodatabase was designed to support the tracking of areas which have achieved backfill verification and incremental bond release, as well as areas that have satisfied performance standards in support of achieving incremental bond release. The incremental bond release process involves the approval of specific requirements for Phase 1 (topsoil applied), Phase 2 partial release (vegetation established) and Phase 3 (reclamation complete). The GPS application of the project involved using a Trimble GeoExplorer series GeoXT during monthly inspections to monitor selected compliance features necessary to support backfill verification and the incremental bond release process. A project specific data dictionary was developed to include the relevant feature types necessary to monitor and verify incremental bond release requirements. Examples include verification of the extent (acreage) and slopes of backfill areas, surveying the centerline of restored creek channels, verification of topsoil application and depth, delineation of restored wildlife habitat features, and mapping of erosion features.

Application of GPS in geomagnetic survey

Abstract When measuring the geomagnetic declination, the azimuth of the reference mark must be measured. This paper briefly describes the principle of measuring the azimuth by the differential GPS (Global Positioning System), several test observations of GPS and the results. In geomagnetic survey in China during 2002~2003, GPS was used in measuring the azimuth. Field observations by GPS were carried out during the period that satellite signals were better received. The statistical results of the GPS data at 135 stations in China show that the difference of the azimuths between 2 GPS measurements at various stations is 0.0″~5.9″ and the average is 1.6″. The azimuthal accuracy measured by GPS in this paper is 0.1′, and it is much better than the azimuthal accuracy 1.0′ given by Newitt et al. (1996). The observation results show that the azimuths measured by GPS are accurate and reliable; they are not related to the time-space changes. The geomagnetic declinations D at various stations were obtained based on the azimuths measured by GPS, and the standard deviation of the reduced value of D was < 0.4′. Using the reduced values, the 8-order spherical cap harmonic model and the 5-order Taylor polynomial model in China for D were obtained. In geomagnetic survey, GPS is also used in measuring the longitude, the latitude and the elevation at various stations.

Using Global Positioning Systems (GPS) and Geographic Information Systems (GIS) in Participatory Mapping of Community Forest in NEPAL

AbstractCommunity forestry is a successful development programme of His Majesty's Government (HMG), in the sector of forest management in Nepal. The process of community forestry comprises the assessment of forest resources and drawing‐up of a plan of action for the management of forests. Forest boundary surveying is a mandatory activity in the formal handing over of the forest to the people or Forest User groups (FUG) as they are known in practice. The spatial issues in mapping are more related to the boundary of the forest, location of the forest itself, the geographic characteristics of the forest i.e. slope, aspect, altitude and area covered by particular forest resources i.e. the forest type, Non Timber Forest Products (NTFPs) and information that could be useful in preparing a better management and implementation plan of the forest. The use of Participatory Geographic Information Systems (PGIS) in the field of community forest management combines the collection of quantitative and qualitative information in a way that is beneficial for the FUG (Jordan, 2000) i.e. mapping the boundary of the forest, block division of the forest area and preparing a multiple resource map. The quantitative spatial components can be collected and managed for sustainable forest management i.e. information on the length of forest boundary, resource distribution, stocking and incidence patterns. Without peoples’ participation in the application of GIS and GPS in mapping the forest, the accuracy cannot always be assured on the one hand, while on the other, the information cannot be properly utilized as the ultimate users of the community forest maps are the local communities themselves. Prior to handing over of the forest areas to the FUGs, transect walks are carried‐out in the relevant areas and features of interest are mapped using GPSs. The data is analysed in a GIS environment and maps i.e. Forest Boundaries, delineating NTFP species as well as the location of poor Households are produced. Assessment of products by plots of the relevant species, are also carried‐out. Thus the participatory GIS, incorporates both indigenous knowledge on spatial aspects of community forest management, as well as social, land cover, and cultural features.

Code tracking architecture influence on GPS carrier multipath

It is well known that carrier-phase multipath is one of the limiting error sources in high-precision differential GPS (Global Positioning System) applications. A thorough understanding of carrier-phase multipath is the first step in the course of mitigating its impact in high precision applications. Complete characterization of carrier-phase multipath error requires a fundamental theoretical description and mathematical modeling. However, the theory and models must be validated with real data. This paper documents the results of a study of the influence of GPS receiver code tracking architecture (coherent and noncoherent) on the carrier-phase multipath error, and provides a thorough validation of carrier-phase multipath theory. Validation is carried out for wide and narrow correlator spacing within coherent and noncoherent code tracking architectures by comparing bench test data to theoretical predictions. Prior to this effort, scant attention had been given to validating carrier-phase multipath theory against GPS data (Townsend et al., 1995). In addition, data collected for non-zero multipath phase rates is presented. The impact of GPS receiver architecture on the mitigation of phase-rate multipath was discussed.

A compact‐sized microstrip antenna for GPS applications

AbstractA microstrip antenna structure is proposed for global positioning system (GPS) applications. This structure is intended to reduce the antenna size at low cost in order to fulfill the increasing needs of mobile devices with GPS functions. Thus, dielectric slabs with low relative permittivity, which can be commonly available on the market at a low cost, are employed. The size reduction is achieved by cutting slits and L‐slots on the surface of the microstrip metal patch in order to lower the resonance frequency of the structure. The numerical and experimental results verify that the antenna design can improve the wide‐angle axial ratio in addition to size the reduction with insignificant reduction of the operation‐frequency bandwidth (still fully sufficient to cover the GPS frequency band). © 2006 Wiley Periodicals, Inc. Microwave Opt Technol Lett 48: 810–814, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.21482

A Novel GPS Patch Antenna on a Fractal Hi-Impedance Surface Substrate

A compact high-performance circularly-polarized microstrip antenna for the global positioning system application is proposed. It comprises a fractal hi-impedance surface electromagnetic bandgap (EBG) structure printed on a high permittivity substrate. Measurements and simulation of return loss and axial ratio are in good agreement. It is shown that the proposed Global Positioning System antenna has good axial ratio performance in the upper half-plane, an improvement in gain and a significantly wider axial ratio bandwidth when compared to the same antenna without EBG

Ambiguity Resolution in GPS-based, Low-cost Attitude Determination

Reliable determination of integer ambiguities is a critical issue in high-precision global positioning system (GPS) applications such as kinematic positioning, fast control surveying and attitude determination. This paper discusses the integer ambiguity resolution procedures in attitude determination using single frequency carrier phase measurements. An optimised ambiguity search algorithm is proposed. This method can not only improve the computation efficiency and reduce the time for resolving ambiguities, but also improve the reliability of the ambiguity solution. The ambiguity search space is determined using float solutions and their variance and covariance matrices estimated by applying Kalman filter algorithm. The integer Gaussian transformation is then used to reduce the size of the search space and Cholesky factorisation algorithm is used to improve the efficiency of the integer ambiguity searching process. Finally, an ambiguity validation method by using the known baseline length and the relationship between the primary and secondary ambiguity groups is presented. The algorithms have been implemented within two low-cost Allstar GPS OEM boards. A number of field experiments have been conducted and the results show that a valid integer ambiguity solution in cold start mode can be identified within 3 minutes.

Differential single-frequency GPS monitoring of the La Valette landslide (French Alps)

Recently, Global Positioning System (GPS) surveying techniques have been increasingly employed to monitor landslide movement. Here we present an application of GPS to monitor the La Valette landslide, located in the Ubaye Valley in the southern French Alps. This complex landslide is composed by an upper rotational part, a central part with generally translational movement and a lower part, which occasionally transforms into mud flows during intense rainfall events. Displacement rates average a few centimeters per month, with velocity peaks of some centimeters per day during periods of strong activity. GPS data presented in this study were acquired with two single-frequency GPS receivers Magellan connected to multipath-resistant antennas. The data were processed with the Magellan software MSTAR. Nine points have been set in the studied area, seven of them in the moving area, one in a stable area near the landslide and one on the facing slope, which is used as reference point. For each observation, one GPS receiver is placed on the reference point for the whole day and the second one is placed on each monitored point for 1-h sessions. The distance between the base and monitored point ranges from 480 to 1660 m. Eight survey campaigns were made between October 2000 and October 2002, to follow the evolution of the surface displacements. The maximum cumulative 3-D displacement observed in the area was about 21 m during the period in the center part of the landslide, corresponding to an average rate of movement of about 3 cm/day. The accuracy achieved during the GPS measurements has been evaluated to be about 2.4 cm in E–W direction, about 11 cm in N–S direction and about 7.4 cm in elevation in the worst case. The GPS results have been compared with traditional surveying techniques (EDM) carried out on the same site by RTM Service (Restauration des Terrains en Montagne). The velocities obtained by the two methods are similar. The advantage of the GPS technique is the collection of data for the three spatial coordinates ( x, y, z) of each point, which allow to calculate the 3-D displacement vector. These measurements have been combined with SAR interferometric data in order to analyse the temporal evolution of the different landslide sectors.

Application of the Real-Time Kinematic Global Positioning System in Bridge Safety Monitoring

A real-time kinematic (RTK) global positioning system (GPS) has been developed and installed on the Humen Bridge (China) for on-line monitoring of bridge deck movement, which may occur as a result of seismic activity, traffic load, and such environmental elements as temperature and wind. This paper presents the main features of the on-line GPS RTK system and its value for on-line safety monitoring.

A compact microstrip antenna for GPS and DCS application

This communication presents a novel design of a compact microstrip antenna practical for both the global positioning system (GPS) and digital communication system (DCS). The proposed antenna consists of two parts: a fundamental mode truncated square patch antenna and a higher-order mode annular ring patch antenna. The truncated square patch operated in right-hand circular polarization at 1575 MHz with 8-MHz CP bandwidth, making the design suitable for the GPS. Further, four slots were embedded into a ground plane to meander the current path of the annular ring patch at the TM/sub 21/ mode, which considerably lowered the resonant frequency and effectively increased the impedance bandwidth. These features reduce the antenna size and make the design appropriate for DCS. Both radiators are placed in a common space but operate independently. The experimental results show that this design is ideally suited for GPS/DCS dual-band mobile communications.

A comparative study of a new GPS reduced-surface-wave antenna

A new global positioning system (GPS) antenna design based on the reduced-surface-wave (RSW) microstrip antenna concept is introduced. In addition to retaining the advantages common to microstrip antennas, these new GPS antennas will be shown to provide comparable performance to the most commonly used GPS antennas, including choke-ring designs. The reduced horizon and backside levels, and good circular polarization characteristics indicate that this new antenna design is ideal for high-precision GPS applications.

The Application of Integrated GPS and Dead Reckoning Positioning in Automotive Intelligent Navigation System

The applications of Global Positioning System (GPS) are increasingly widespread in China. GPS positioning is more and more popular. Especially, the automotive navigation system which relies on GPS and Dead Reckoning technology is developing quickly because of the anticipated huge future market in China. In this paper a practical combined positioning model of GPS/DR is put forward. This model designed for automotive navigation system makes use of a Kalman filter to improve position and map matching veracity by means of filtering the raw GPS and DR signals. In practical examples, the validity of the model is illustrated. Several experiments and their results of integrated GPS/DR positioning in automotive navigation system will show that a Kalman Filter based on integrated GPS/DR position is necessary, feasible and efficient for automotive navigation application. Certainly, this combined positioning model, similar to other models, can not resolve all situation issues. In the paper, the applicable principles of the model are given and the advantages and disadvantages of this model are compared with other positioning models. Finally, suggestions are given for further improving integrated GPS/DR system performance, and the application aspects of integrated GPS/DR technology in the automotive navigation system are summarized.

Accuracy and reliability of map-matched GPS coordinates: the dependence on terrain model resolution and interpolation algorithm

The global positioning system (GPS) has become the most extensively used positioning and navigation tool in the world. Applications of GPS abound in surveying, mapping, transportation, agriculture, military planning, GIS, and the geosciences. However, the positional and elevation accuracy of any given GPS location is prone to error, due to a number of factors. This has serious implications for some applications, such as real-time navigational systems. GPS accuracy can be significantly improved with additional data, possibly from multiple sources, and especially from multiple receivers. In the case of a single GPS receiver, its position and elevation can be considerably improved with the use of spatial data. For vehicle tracking, map matching can be employed to intelligently snap the GPS location to a road centreline, while height aiding can augment the GPS solution by utilising a digital terrain model (DTM), thereby reducing the number of satellites required to determine a position. This paper describes the use of map matching and height aiding, and examines the effect of different terrain resolutions (Ordnance Survey 1:50,000 and 1:10,000 scale DTMs) on plan position and elevation accuracy for vehicle tracking. Furthermore, the user's choice of interpolation algorithm for estimating heights from the DTM is investigated. The results of the experiments described in this paper demonstrate that height aiding alone reduces the mean error in elevation from 22.5 to 17.5 m for of a single GPS receiver, and the mean error in plan position from 6 to 5 m. However, map matching and height aiding combined, reduces the elevation RMSE of a single GPS receiver from 22.5 m to approximately 4 m (1:50,000 scale DTM) and down to 0.8 m (1:10,000 scale DTM), while the plan position RMSE is reduced from 5.9 to 3.2 m (either DTM). It is also demonstrated that when the number of satellites visible to the receiver is reduced, or the satellite geometry is poor, map matching and height aiding considerably improves the plan and elevation accuracy. The use of a higher-order interpolant (e.g. a bicubic or biquintic polynomial) is shown to slightly improve performance, compared to a bilinear interpolant, for the lower-resolution DTM, but has little overall benefit for the higher resolution DTM.